Asymptomatic critical hypoglycaemia: a dangerous presentation of glycogen storage disease type Ib in infancy.

UNLABELLED: We report the case of a 3-month-old boy who presented with a 3-day history of respiratory tract infection and poor feeding. He was incidentally found to have profound hypoglycaemia, high-anion-gap lactic acidosis, ketonuria, hyperlipidemia, hepatomegaly, growth failure and neutropenia. Glycogen storage disease type Ib (GSD Ib), an autosomal recessive metabolic defect of the microsomal transporter glucose-6-phosphate-translocase, was suspected and confirmed by genetic testing. Treatment consisted of initial intravenous glucose and fluids to correct his lactic acidosis, followed by a strict dietary protocol consisting of soy-based infant formula enriched with glucose polymers from cornstarch and overnight gastrostomy feeds.

CONCLUSIONS: GSD I should be considered in all young children presenting with hypoglycaemia and lactic acidosis. Presence of neutropenia further confirms GSD Ib. Even critical hypoglycaemia can be clinically unapparent in affected children.